#include "sha1.h"
#include <string.h>

namespace hash
{
#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

#if BYTE_ORDER == LITTLE_ENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00)|(rol(block->l[i],8)&0x00FF00FF))
#elif BYTE_ORDER == BIG_ENDIAN
#define blk0(i) block->l[i]
#else
#error "Endianness not defined!"
#endif
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15]^block->l[(i+2)&15]^block->l[i&15],1))

#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);

	static void transform(uint32_t state[5], const unsigned char buffer[64])
	{
		uint32_t a, b, c, d, e;
		typedef union
		{
			unsigned char c[64];
			uint32_t l[16];
		} CHAR64LONG16;
		CHAR64LONG16 block[1];
		memcpy(block, buffer, 64);

		a = state[0];
		b = state[1];
		c = state[2];
		d = state[3];
		e = state[4];
		R0(a, b, c, d, e, 0);
		R0(e, a, b, c, d, 1);
		R0(d, e, a, b, c, 2);
		R0(c, d, e, a, b, 3);
		R0(b, c, d, e, a, 4);
		R0(a, b, c, d, e, 5);
		R0(e, a, b, c, d, 6);
		R0(d, e, a, b, c, 7);
		R0(c, d, e, a, b, 8);
		R0(b, c, d, e, a, 9);
		R0(a, b, c, d, e, 10);
		R0(e, a, b, c, d, 11);
		R0(d, e, a, b, c, 12);
		R0(c, d, e, a, b, 13);
		R0(b, c, d, e, a, 14);
		R0(a, b, c, d, e, 15);
		R1(e, a, b, c, d, 16);
		R1(d, e, a, b, c, 17);
		R1(c, d, e, a, b, 18);
		R1(b, c, d, e, a, 19);
		R2(a, b, c, d, e, 20);
		R2(e, a, b, c, d, 21);
		R2(d, e, a, b, c, 22);
		R2(c, d, e, a, b, 23);
		R2(b, c, d, e, a, 24);
		R2(a, b, c, d, e, 25);
		R2(e, a, b, c, d, 26);
		R2(d, e, a, b, c, 27);
		R2(c, d, e, a, b, 28);
		R2(b, c, d, e, a, 29);
		R2(a, b, c, d, e, 30);
		R2(e, a, b, c, d, 31);
		R2(d, e, a, b, c, 32);
		R2(c, d, e, a, b, 33);
		R2(b, c, d, e, a, 34);
		R2(a, b, c, d, e, 35);
		R2(e, a, b, c, d, 36);
		R2(d, e, a, b, c, 37);
		R2(c, d, e, a, b, 38);
		R2(b, c, d, e, a, 39);
		R3(a, b, c, d, e, 40);
		R3(e, a, b, c, d, 41);
		R3(d, e, a, b, c, 42);
		R3(c, d, e, a, b, 43);
		R3(b, c, d, e, a, 44);
		R3(a, b, c, d, e, 45);
		R3(e, a, b, c, d, 46);
		R3(d, e, a, b, c, 47);
		R3(c, d, e, a, b, 48);
		R3(b, c, d, e, a, 49);
		R3(a, b, c, d, e, 50);
		R3(e, a, b, c, d, 51);
		R3(d, e, a, b, c, 52);
		R3(c, d, e, a, b, 53);
		R3(b, c, d, e, a, 54);
		R3(a, b, c, d, e, 55);
		R3(e, a, b, c, d, 56);
		R3(d, e, a, b, c, 57);
		R3(c, d, e, a, b, 58);
		R3(b, c, d, e, a, 59);
		R4(a, b, c, d, e, 60);
		R4(e, a, b, c, d, 61);
		R4(d, e, a, b, c, 62);
		R4(c, d, e, a, b, 63);
		R4(b, c, d, e, a, 64);
		R4(a, b, c, d, e, 65);
		R4(e, a, b, c, d, 66);
		R4(d, e, a, b, c, 67);
		R4(c, d, e, a, b, 68);
		R4(b, c, d, e, a, 69);
		R4(a, b, c, d, e, 70);
		R4(e, a, b, c, d, 71);
		R4(d, e, a, b, c, 72);
		R4(c, d, e, a, b, 73);
		R4(b, c, d, e, a, 74);
		R4(a, b, c, d, e, 75);
		R4(e, a, b, c, d, 76);
		R4(d, e, a, b, c, 77);
		R4(c, d, e, a, b, 78);
		R4(b, c, d, e, a, 79);
		state[0] += a;
		state[1] += b;
		state[2] += c;
		state[3] += d;
		state[4] += e;
	}

	sha1::sha1()
	{
		state[0] = 0x67452301;
		state[1] = 0xEFCDAB89;
		state[2] = 0x98BADCFE;
		state[3] = 0x10325476;
		state[4] = 0xC3D2E1F0;
		count[0] = count[1] = 0;
	}

	void sha1::update(const unsigned char* buf, size_t len)
	{
		uint32_t i;
		uint32_t j = count[0];
		if ((count[0] += len << 3) < j) {
			count[1]++;
		}
		count[1] += (len >> 29);
		j = (j >> 3) & 63;
		if ((j + len) > 63)
		{
			memcpy(&buffer[j], buf, (i = 64 - j));
			transform(state, buffer);
			for (; i + 63 < len; i += 64)
			{
				transform(state, &buf[i]);
			}
			j = 0;
		}
		else
		{
			i = 0;
		}
		memcpy(&buffer[j], &buf[i], len - i);
	}

	void sha1::final(unsigned char* digest)
	{
		unsigned char finalcount[8];
		for (unsigned i = 0; i < 8; i++)
		{
			finalcount[i] = (unsigned char)((count[(i >= 4 ? 0 : 1)] >> ((3 - (i & 3)) * 8)) & 255);
		}
		update((const unsigned char*)"\x80", 1);
		while ((count[0] & 504) != 448)
		{
			update((const unsigned char*)"\x00", 1);
		}
		update(finalcount, 8);

		for (unsigned i = 0; i < 20; i++)
		{
			digest[i] = (unsigned char)((state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
		}
		memset(&state, '\0', sizeof(state));
		memset(&count, '\0', sizeof(count));
		memset(&buffer, '\0', sizeof(buffer));
	}
}
